Recent tracking polls report that about one in eight people have taken a glucagon-like peptide-1 receptor agonist, more commonly known as GLP-1 medications.
Originally used to help treat type 2 diabetes, these medications have gained in popularity over the last few years for weight loss.
Currently, the most common types of GLP-1 drugs are semaglutide — sold under the brand names Ozempic for type 2 diabetes and Wegovy for weight loss — and tirzepatideTrusted Source, sold under the brand names Mounjaro for type 2 diabetes and Zepbound for weight loss.
Just like any medication, GLP-1 drugs have possible side effects and complications. One potential complication was first reported in July 2024 when a study found people using semaglutide were at a four times higher riskTrusted Source of developing nonarteritic anterior ischemic optic neuropathy (NAION). This was followed by research published in January 2025 that discovered people taking either semaglutide or tirzepatide may be at an increased risk for potentially blinding vision issuesTrusted Source.
For this study, researchers analyzed health records from 2020 to 2023 of more than 139,000 Ontario residents with an average age of 66 and diagnosis of diabetes. Participants who used GLP-1 medications did so for more than six months.
“Our study included any GLP-1 receptor agonists that were prescribed during the study period in Ontario, Canada; we did not exclude any specific type of these medications,” Rajeev H. Muni, MD MSc FRCSC, associate professor and vice chair of Clinical Research in the Department of Ophthalmology and Vision Sciences at the University of Toronto in Canada, and principal investigator of this study explained . “However, semaglutide represented the vast majority of use in our cohort, accounting for 97.5% of all GLP-1 prescriptions.”
Older adults taking GLP-1s at 2-fold higher risk
Upon analysis, researchers found that participants with diabetes taking a GLP-1 medication had a two-fold higher risk of developing nAMD — a type of AMD where malformed blood vessels grow underneath the retina, causing fluids to leak into the macula of the eye.
There is currently no cure for nAMD and it is a condition that can potentially cause blindness.
“We found that among patients with diabetes aged 66 and older, the incidence of nAMD was approximately 1 in 1,000 in those who had never used GLP-1 receptor agonists, compared to about 2 in 1,000 among those who had been exposed to these medications for at least six months,” Muni said. “While the absolute risk remains low, this represents a relative doubling in risk.”
“While our findings should not prompt alarm, they do warrant increased clinical awareness,” he continued. “These medications have well-established benefits for cardiovascular, renalTrusted Source, and metabolic healthTrusted Source. However, patients who may be at higher risk for nAMD, such as older adults, should be aware of the possibility of new visual symptoms. If any new changes in vision occur while taking these medications, patients should promptly inform their doctor and be referred to an ophthalmologist for further assessment.”
